Method for eliminating airborne microorganisms

ABSTRACT

A method for eliminating airborne microorganisms in an air duct comprises placing a device containing at least one light emitting diode (LED) in the air duct so that the air flow passes through the beam emitted by the LED.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation-in-part of U.S. patent application Ser. No.10/241,620, filed on Sep. 11, 2002, the disclosure of which is hereinincorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a method for the elimination or destruction ofa wide variety of microorganisms, particularly harmful bacteria in theair.

2. The Prior Art

In the early years prior to the present invention, light emitting diodes(LED) did not produce light of sufficient intensity for manyapplications since they required a lot of power and in some instancesextra cooling. Moreover, the typical life estimates of high outputultraviolet LED's was so short as to render them unsatisfactory for manyuses. More recently, however, due in part to the advances made by theNASA Marshall Space flight Center and others, the technology relating toLED's has advanced dramatically. The present day LED's have becomeextremely powerful, cold to the touch and require very little energy.

Accordingly, light emitting diodes are now finding a wide variety ofapplications in both industrial and medical fields. For instance thenewer LEDs are now capable of destroying a wide variety ofmicroorganisms, particularly bacteria which cause skin infectionsincluding staph, strep and the like. LEDs have also been found to beuseful in the destruction of the small pox virus, anthrax and the like.

Much of the published experimental work done by NASA with LEDs relatesto the affects of LEDs on cells, muscle and bone since it had beenobserved that normal wound healing and cell growth are negativelyaffected by diminished gravity as is encountered in space. It has beenobserved that the applications of light therapy with the use of LEDssignificantly improved wound healing and cell and bone growth ofastronauts on long term space missions.

Another area of technology in the medical field is the use of LEDs inphotodynamic therapy where an injected photosensitizer such as in cancertherapy, concentrates in a tumor, and when activated by a light source,can destroy the tumor.

Prior to the advance in LED technology, low level laser therapy had beenused for performing therapy on patients particularly for the managementand symptomatic relief of pain. The low level laser therapy could reachdeep into tissues and yet without harm to the tissues. However, thecombined wavelengths of light which are optional for wound healingcannot be efficiently produced and the size of wounds that can betreated by lasers is severely limited. Hence, LEDs offer an effectivealternate to lasers for many applications, including pain therapy. LEDsare safe, non-invasive, drug free and therapeutic. It is believed thatLED treatment stimulates natural physiological changes in the cells of apatients' body and helps to relieve pain naturally.

Although the use of ultra violet light for the sterilization ofmicroorganisms was not practical up to the present due to the estimatedlimited life span of high output ultraviolet light emitting diodes, morerecently technology has been developed high power ultra violet emittingdiodes which have much longer spans. For example, it is now possible tohave systems of 500 milliamps as opposed to the lower earlier systems of30 milliamps.

Accordingly, the interest in developing method for sterilization of airand surfaces, including the treatment of human tissue, with LED's hasincreased markedly.

However, prior to the present invention, the devices presently used weresomewhat cumbersome and tied to a fixed energy source which limitedtheir portability. The present invention, therefore, has provided asmall device which can be obtained in the form of a kit and useful for avariety of applications.

It is therefore an object of the present invention to provide a small,compact ultra-violet LED device which is useful in the destruction ofmicroorganisms, and in particular, harmful bacteria. The device is alsouseful in a wide variety of therapeutic treatments. Another object ofthis invention is to provide a device which is compact and has its ownindependent energy source or can be connected to an existing energysource. A still further object is to provide a device which can be usedto destroy bacteria that can cause pimples, boils, infections, and thelike. Another aspect of this invention is to provide an LED device whichemits a strong ultra-violet light source capable of penetrating throughseveral layers of skin to destroy infectious bacteria or to bestrategically placed to kill airborne bacteria. A still further objectis to provide a hand held device which contains restraints to avoidaccidental activation of the LED or unnecessary exposure to emittedlight. Another object of this invention is to provide a device whichcontains a timer to limit the interval that the device is on. A stillfurther object is to provide methods for utilizing the device of thepresent invention for the destructions of microorganisms and thetreatment of various patient conditions. Another object is to provide akit comprised of the device, preferably in the shape of a pen, battery,battery recharger and goggles for eye protection. Another object is toprovide a device for placement in an air duct to decontaminate airflowing through the air duct.

These and other objects will readily become apparent to those skilled inthe art in light of the teachings herein set forth.

SUMMARY OF THE INVENTION

In its broad aspects, the present invention is directed to a devicecontaining at least one light emitting diode (LED) which is useful bothfor the destructions of microorganisms and for therapeutic purposes. Thedevice being comprised of an enclosure having:

(a) at least one unidirectional light emitting diode (LED); disposed soas to emit light from the device and having a child proof protectivemeans to prevent unintentional exposure to light emission;

(b) a rechargeable or direct power source to activate the diode.

In addition to the hand held device, the present invention is alsodirected to a method for using the device for elimination ofmicroorganisms in the air. A kit is also provided which contains thedevice and a power source.

BRIEF DESCRIPTION OF THE DRAWINGS

The device of the present invention will be better understood byreference to the drawings wherein:

FIG. 1 is a perspective view of a hand-held, light emitting diode devicein the shape of a pen useful for the destruction of microorganisms;

FIG. 2 illustrates the hand-held device of FIG. 1 and depicts it beingheld by a medical technician or physician for the treatment ofmicroorganisms on a surface; and

FIG. 3 shows the device installed in an air duct for use indecontaminating air flowing through the duct.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings, and more particularly to FIG. 1, the device10 of the present invention is shown in the shape and approximate sizeof a pen having a barrel containing zone 12 which contains one or morelight emitting diodes, zone 14, which contains the rechargeable powersource, switch assembly 16 which has child proof restraints to preventinadvertent activation of the device; timing means 18 to control anddeactivate the device after a set time interval; and zone 20 from whichthe light is emitted in a unidirectional manner and which also containschild proof restraint means to prevent accidental light emission.

FIG. 2 depicts a physician or technician holding the device of thisinvention and directing the light to a surface 22 which could containbacteria or could be the skin of a patient in need of treatment, forexample, of an infection. Under the skillful hands of a physician orsurgeon, the device can be employed for treating infections in the oralcavity, or other areas of a patients' body.

As indicated above, low level laser technology has in the past beenemployed for the therapeutic management a relief of pain in humans. Forexample, in U.S. Pat. No. 5,464,436, which issued Nov. 7, 1995, there isdescribed a method of treating the external skin layer of a patient witha laser source which emits a laser light having a wave-length between800 nm and 870 nm and at a level of 1 joule/cm² for each treatmentcycle. It is indicated in this patent that while laser light ofconventional systems can penetrate skin layers and cause injury to apatient, the use of a low level laser light therapy (LLLT) can reachinto deep tissues to provide beneficial effects without doing harm tothe tissue. In contract, the device of the present invention does notemploy a laser source and due to the advances in LED technology isbelieved to be much safer and as efficient.

In practice it has been found that the device of the present inventionprovides wavelengths in the ultra violet range of about from 200 to 450nanometers and higher, and energy levels of up to 35,000 microwattseconds/cm², which are necessary to eliminate or destroy mostmicroorganisms such as bacteria, spores, algae and viruses. Mostbacteria can be destroyed at ultra violet energies of from about 3,000to about 5,000 microwatt-seconds/cm² while mold spores may requireenergies in the 20,000 to 35,000 mW-seconds/cm².

In contrast to the commercial systems for ultra violet lightsterilizations which are costly and difficult to maintain, LEDtechnology has become of particular interest since systems which usethis technology are at least as efficient and can operate for muchlonger periods of time than in the past.

In addition to its use in the destruction of microorganisms and fortherapeutic applications, the device of the present invention is alsouseful in photodynamic therapy for activating photosensitizers.Improvements in semiconductor technology has greatly increased the lightoutput of LED chips and has rendered them particularly attractive forvarious applications. For example, aluminum-gallium-arsenide is anexcellent semiconductor and LEDs which have been manufactured from suchcomposition are particularly attractive for use the absorption spectrumof certain photosensitizes such as lutetium texaphyrin andbenzophorphyrin derivatives which are currently finding use in thetreatment of brain tumors.

The enclosure for the power source and LED can be pen-like in shape forease of handling as depicted in FIG. 2, or it can be fabricated in otherconfigurations as well. As shown in FIG. 1 the power source ispreferably located in the rear section which can be threadably attachedto the other section and easily removed when the batter power sourceneeds recharging. Alternatively, the section containing the battery canhave a lid opening allowing for a recharger to be temporarily connectedto the battery without its removal from the enclosure.

FIG. 3 shows the device 24 installed in a typical air duct, so that air27 flowing through duct 25 along the arrows passes through beam 26 andis decontaminated before entering the room through register 30 on wall31. In this embodiment, device 24 is not pen-shaped but is configuredmore box-like as a hollow tube with the LEDs 28 inside cleaning the airthat passes through it for simpler installation in air duct 25. Device24 could be installed in ducts that enter rooms through walls, floorsand ceilings, and can be mounted in a variety of ways. It is preferableif device 24 is mounted so that beam 26 is positioned perpendicular tothe air flow 27. An exhaust fan is added to the inside of the hollowenclosures forcing air through the chamber in the duct system. Device 24can be mounted via any conventional means, such as by a bracket, screw,adhesive or any other suitable mounting means. Device 24 could also beinstalled in air ducts of automobiles, air planes, cruise ships, or anyother structure. Of particular importance is its use in hospitals. A fan32 could be placed in the duct to further direct air past beam 26 of the

wind tunnel

device 24.

The battery and the recharger are commercially available items. Thebattery will, of course, have sufficient power to provide the necessaryenergy levels indicated above for activation of the LED, and for thedestruction of microorganisms as well as for therapeutic treatment.Direct power sources may be included in the duct variation since thelife span of LED's are now up to 15 years under continuous operation.

The particular diodes employed in the device of the present inventioncan be selected from a variety of crystals or chips depending upon theparticular wave length desired

A wide variety of inorganic electroluminescent compounds can be used asthe light emitting diode. These compounds, or phosphors, arecommercially available in crystal form. When exposed to an electricalcurrent they fluoresce at different wavelengths depending upon theparticular chemical composition of the phosphor and in many instancesthe kind of impurities present in, or added to, the phosphors.

Typical phosphors include but are not limited to, crystal compounds suchas cadmium selenide, zinc sulfide, cadmium sulfide, mercury sulfide,zinc sulfide doped with copper, complexes of chromium, lithium andgermanium oxides, complexes of zinc, cadmium, and selenium, yttriumoxysulfide and the like.

Of more recent interest are some of the organometallic compounds whichare electroluminescent and in some instances may be competitive with theinorganic compounds presently in use as LED's.

Although the device of the present invention is deemed to be safer andat least as efficient as devices which employ lasers, it is not entirelywithout danger and reasonable cautions must be followed in its use. Thedevice should only be used by technicians or medical personnel who havebeen trained in its use and who wear proper eye protection.

Accordingly, to maximize safety the device of the present hand heldinvention has restraints on both the switch assembly and the point wherelight is emitted. Several known child proof features or a combination offeatures can be employed to prevent accidental or unauthorizedactivation of the device. For example, it may be necessary to twist onesection of the pen-shaped device while simultaneously pressing down onthe switch assembly to allow the device to be activated or a shuttermechanism to be opened to permit light emission.

Additionally, the hand held device includes a built-in timer which willallow the device when activated to emit light for a predeterminedinterval and then automatically turn off. Such timing devices are knownin the art and are commercially available.

While the invention is directed to a hand held device which is free of aconnection to an external power source, in some instances it may bedesirable to be able to plug in the device to an external source via anappropriate extension cord.

Although the invention has been illustrated by the preceding disclosure,it is not to be construed as being limited to the materials employedherein, but rather, the inventions pertains to the generic area ashereinbefore disclosed. Various modifications and embodiments thereofcan be made without departing from the spirit and scope thereof.

1. A method for the destruction of airborne microorganisms, comprising:installing in an air duct a device having an enclosure and at least oneunidirectional light emitting diode (LED) disposed so as to emit lightfrom the enclosure, so that light emitted by the LED is aimed to a flowof air in the air duct.
 2. The method of claim 1, wherein the emittedlight is ultra-violet.
 3. The method of claim 1, wherein the source oflight emitted is from an aluminum gallium arsenide crystal.
 4. Themethod of claim 1, wherein the device has a rechargeable power source.5. The method of claim 1, wherein the device is installed in a heatingduct.
 6. The method of claim 1, wherein the device is installed in anair-conditioning duct.
 7. The method of claim 1, further comprising thestep of placing a fan inside the air duct to force air past the beamemitted by the LED.